The government alleges that Manning provided the anti-secrecy website Wikileaks with more than 700,000 secret documents and diplomatic cables. In January prosecutors said they would introduce evidence that WikiLeaks materials were found at Osama bin Laden's safe house.

Manning has not denied his culpability. In February, he pleaded guilty to 10 of 22 charges.

"I wanted the American public to know that not everyone in Iraq and Afghanistan are targets that needed to be neutralized, but rather people who were struggling to live in the pressure-cooker environment of what we call asymmetric warfare," Manning said.

Manning is one of six people the Obama administration has prosecuted under the Espionage Act, more than all previous administrations combined.